Carrying pictures of the trainee teachers who vanished on September 26, the yesterday's protest in Chilpancingo, capital of the crime-plagued state of Guerrero, was led by some of the anguished parents, who refuse to believe their children are dead.
Some demonstrators wielded sticks, pipes and riot shields stolen from police, but there was no repeat of the violence that has broken out at several other rallies this week.
Authorities say the students were abducted in Iguala, in Guerrero state, by police and handed over to a drug cartel before being murdered and set alight -- a claim contested by the victims' families.
"We cannot give up, someone has to answer for these crimes," local activist Osmin Valdez said.
Activists say the students were attacked by police and abducted amid fears they planned to disrupt a speech given by the wife of local mayor Jose Luis Abarca, who was arrested on November 4.
Protests have rocked a number of Mexican cities this week, with the Guerrero state congress set ablaze on Tuesday in the escalating demonstrations.
Mexico's Senate on Thursday voted to sack the head of the country's National Human Rights Commission, Raul Plascencia, over his handling of the crisis that has rattled the government of President Enrique Pena Nieto.
Plascencia will be replaced by former prosecutor Luis Raul Gonzalez.
Outgoing rights chief Plascencia has also been rebuked for a recent investigation into the military's killing of 22 gang suspects in the central Mexican town of Tlatlaya.
Some 100,000 people have died or gone missing since Calderon launched the offensive against drug gangs eight years ago.
